1. Technical Field
The present invention relates to a method for manufacturing gas generating material, and in particular relates to a method for manufacturing a gas generating material which contains an azide and a metal oxide and is used for generating gas to inflate a vehicle occupant restraint, such as an airbag.
2. Description of the Prior Art
U.S. Pat. No. 3,996,079 discloses a process for manufacturing an azide-containing gas generating composition. The dry ingredients of the gas generating composition are mixed together. A liquid is then added to the dry mixture to produce a plastic mass. Suitable liquids are water and ethanol. The liquid is about 15% by weight of the total composition and dissolves the finer particles of the azide ingredient. The plastic mass is then forced through a die, perforated plate, or sieve to form wet granules. The wet granules are then dried.
U.S. Pat. No. 4,758,287 also discloses a process for manufacturing an azide containing gas generating material. In this process a water slurry of gas generating material is prepared. The slurry is then molded into a desired shape and flash dried.
The known methods of making gas generating material which contains an azide and a metal oxide have not been entirely satisfactory because of a number of factors. In some known processes, the materials are mixed in dry form, which creates a safety hazard. Also, special precautions must be taken to guard against production of hazardous byproducts which can affect persons who come into contact with the by-products. Finally, the known processes do not provide for conserving materials.